Building material



y 1932- G. H. ELLIS 1,858,217

BUILDING MATERIAL Original Filed July 9, 1928 2 Sheets-Sheet l May 10, 1932. G. H. ELLIS BUILDING MATERIAL 2 Sheets-Sheet 2 Original Filed July 9, 1928 A TTOENE' Y;

Patented May 10, 1932 UNITED STATES PATENT oFFIcE GEORGE E. ELLIS, OF ST. PAUL, MINNESOTA, ASSIGNOB TO THE INSULITE OOIPANY, OF MINNEAPOLIS, MINNESOTA, A CORPORATION OF MINNESOTA BUILDING MATERIAL Original application filed July 9, 1928, Serial 1T0. 291,855. Divided and this application filed February 17, 1930. Serial No. 429,085.

This invention relates to new and useful improvements in building material, and more particularly to composition boards and walls constructed therefrom, said composi- .tion boards being adapted for application either inside. or outside of the studding or floor joists, and receiving coatings of plaster, cement or stucco.

An object of the present invention is to provide a composition board having its opposite edges corner beveled in a manner to provide depressions between contiguous oards, when secured to a support and abuttingly engaged, so that when plaster or other coating material is applied to the surfaces of the boards, such material will be thicker in the region of the joint, thus increasing its strength and reducing to a minimum the possibility of the (plaster cracking, as a result of expansion an contraction of the composition boards, when subjected to moisture, as when plaster is applied to the surfaces there- This application is divisional of my coending application, Serial Number 291,355 ed July 9th, 1928. Other objects are to provide a structure comprising a plurality of adjacently disposed slabs, the slabs being formed to provide spaced depressions for increasing the depth of plaster at the joint on the plaster-receiving side; to have plasterreceiving depressions of substantial area arranged at intervals across the joints; and to provide a composition board or slab which is provided with notches so arranged that corresponding notches in an adjacent board are adapted to register and provide a recess across the joint to receive plaster and thus reinforce the plaster in the region of the joints, whereby cracking of the plaster at these points, due to expansion and contracting movements of the boards, is largely overcome.

Another, and more general, object is to provide an improved composition or fiber board as a base for plaster or other material, having means for increasing the thickness of the plaster at the joints of contiguous boards, and in which the edges of the boards with the recesses 10 provi are adapted for overlapping engagement, to

provide a sealed, yet expansible, omt.

Features of the invention include, among the broader ideas of means, all details of construction.

Advantages of the invention will also be set forth in the description of the dravvin forming a part of this application, and in said drawings Figure 1 is a perspective view illustrating a wall constructed in accordance with the teachings of this invention;

Figure 2 is a perspective view of one of the elements of the wall shown in Figure 1;

Figure 3 is an enlarged detail section on line 33 of Figure 1;

Figure 4 is a section positionally corresponding to line 33 but showing a modification; and

Figure 5 is a section positionally corresponding to line 3-3 of Figure 1, showing another modification.

Referring first to Figure 1, the studding is indicated at 1, and the slab element is generally indicated 2. Each slab is provided at opposite longitudinal edges with reversely arranged recesses respectively indicated 3-4, and formed in this instance by corner-notching or rabbeting. The recesses face in opposite directions at opposite face sides of the board. Referring to Figures 1 and 3 it will be noted that the upper and lower edges of the boards are overlapped to provide an expansion joint, andthat the depth of one of the rabbets, measured crosswise of the board, is greater than the other, to provide a longitudinally disposed recess or depression 6, to

increase plaster thickness at the joint. At indimensions than recesses 6. 'The recesses 6,

10, together provide for an increased depth of plaster throughout the length of the joint, 111g for a larger 5 boards absorb considerable moisture causing them to expand and'later contract, and ordinarily without provision for increased depth of plaster at the joint, cracking takes'place.

Figure 4 shows a modification in which the notches are cut in a manner to provide slotlike openings 20 between the edges of adjacent boards at the back, so that the plaster at the joint extends therethrough as at 21 to form a key.

In the form of the invention shown in Figure 5, the notches are cut with a circular cutter and therefore the bottom of the notches are curved as at 22. This is a very economical method of forming the recesses. The plaster is indicated at 23 and its greatest depth at the joint at 24.

Although in the drawings the horizontal edges only have been recessed, it will be understood that the ends also may be recessed.

It will be noted thatthe depressions 10 are formed crosswise of and intersect the depres sion 6 at intervals. This arrangement largely revents the plaster from cracking the full ength of the joint. Ordinarily if cracking starts, it willoften continue throughout its entire longitudinal extent, but with the present construction this extended character of cracln'ng does not take place because of the interposition of the reinforcement provided by relatively wide plaster plugs 24, the contained plaster of which is continuous with that of the depressions 6. Another feature of this invention consists in applying these notches at the ends of the slabs to formdepressions thereacross, theends-being separated to provide for an increased depthof plaster. This feature is shown in Figure 1, wherein the ends are spaced to provide the depression 12, and the notches 11 coo erate to form depressions of greater area, ut of less longitudinal extent than the depressions I claim as my invention:

1. A plurality of boards having edge portions reduced in thickness and overlapped to form an expansion joint, said edge portions-- bein cut away to provide an open oint on the ace side, said edge portions being notched at intervals also on the face side to provide transverse enlargements of the open joint which extends transversely of and extends laterally at both sides of the open joint, whereby alternate wide and open joint portions are provided which form, when the plaster enters the open joint, a longitudinally continuous plaster key having alternate wider and narrower portions.

2. A structure comprising a plurality of adjacently disposed slabs having opposed edges spaced apart to receive plaster therebetween, the faces of the slabs having depressions therein which transversely intersect and extend laterally beyond the spaced-apart edges, said depressions bein arranged in spaced relation lengthwise of the joint.

3. In a wall, a plurality of adjacently arranged boards the edge portions of said boards being arranged in spaced relation to provide a plaster key groove, and the faces of the boards being notched to provide 0 posed recesses which cooperate to provide epressions which are disposed crosswise of, and which extend transversely laterally beyond the groove throughout only a portion of its longitudinal extent.

4. A structure comprising a plurality of adjacently disposed slabs the edges of which are spaced to form open joints for receiving plaster, the slabs being provided with depressions which transversely intersect and extend transversely beyond the open joints.

5. A structure comprising a plurality of adjacently disposed slabs having opposing edges spaced apart to provide elongated grooves to recelve facing plaster to form keys, the edges of the slabs being notched at intervals to widen the grooves for receiving a larger amount of laster and form pluglike plaster keys w ich are integral with I the plaster of the narrower grooves.

6. In a wall, a plurality of adjacently arranged boards the cd c portions of certain boards being arranged in spaced relation to forin plaster key grooves the plaster-receiving faces .o the boards having notches opposed and coperative to widen the groove and to provide outwardly flared depressions which are spaced lcn thwise of the rooves, and which receive and form plaster p ug-like keys which are continuous with the keys formed by the first mentioned grooves.

7. A slab for the purpose described, having notches in its plaster face at intervals along each of two opposite ed es the notches being slanted downwardly andoutwardl toward the edges, and intersecting the e ges, whereby respective notches of a plurality of slabs can be registered to form outwardly flared depressions which are spaced len hwise of the joint formed by the opposed e ges of respective slabs. I

8. A slab for the purpose described having notches in its plaster face at intervals along each of two opposite edges, the notches beemar? be registered to form outwardl flared deresslons which are spaced lengt wise of the oint formed by the opposed edges of respective slabs.

In witness whereof, I have hereunto set my hand this 14th day of February, 1930;

GEORGE-H. ELLIS. e 

